The project will aim at determining the extent and neurological basis of the bahavioral sparing or loss that follows localized perinatal brain damage in the visual cortex of cats. We plan to examine the relations among: 1) Extent and location of perinatal damage to the visual and extravisual cortex 2) capacity for depth and pattern discrimination and 3) extent and nature of photically evoked activity in the extravisual cortex. Kittens will receive cortical lesions when 3 days old and will be tested as juveniles or as adults on a visual cliff and on tasks involving the discrimination of patterns. The major project to be undertaken will compare the effects of lesions in the visual cortex made in infancy or adulthood on tasks demanding visually guided behavior. The study is designed to control for both postoperative recovery interval and age at the time of behavioral testing.